Rotational mechanisms are frequently seen in our daily life being operated in different ways. Conventional cooling fan or hot-air fan can rotate to and fro in a preset angular distance. On the other hand, a stationary article being suspended is frequently used. The reason of the preceding arrangement is to accommodate the environment.
Taking a cold-air or hot-air casing body as an example, the conventional way is to provide an upright frame attached with a cold-air or hot-air casing body and a crank is driven by an eccentric shaft of a motor. Then, the crank actuates a pivot to allow the cold or hot air casing body rotating to and fro in a preset angular distance.
Although the preceding structure can perform basic rotational function, the deficiency of the conventional way resides in that the cold or hot air casing body moves over the space surrounded by the frame such that a space available for rotation of the casing body has to be reserved in advance. Besides, movement at an open space often creates some problems concerning safety.